1. Field of the Invention
This invention relates generally to devices for positioning of medical instruments such as needles for accurate percutaneous insertion, and more particularly to devices for such positioning of needles and other medical instruments in combination with X-ray emissions.
2. Description of the Prior Art
The conventionally and widely used "CAT Scan" device, a computer controlled X-ray instrument which can provide cross-sectional imaging of body tissues, is a very powerful modern instrument which has a wide range of uses. One such use is the precise location of body tissues which are desired to be accessed, as by use of long, thin needles or other medical instruments (such as catheters) by percutaneous insertion, for taking biopsy samples of such target tissues or for further medical treatment (such as draining abcesses or removing foreign bodies therefrom).
However, currently trial and error methods are used to insert such needles and medical instruments in response to the cross-sectional images generated by the CAT Scan device, in order to puncture the skin and reach the desired target point. This can result in repeated puncturing of the skin which carries with it the enhanced risk of damage to body organs adjacent to the target point lying along the path which the needle is desired to travel. Moreover, many target points may lie too close to vital nerve or other body tissues, or no safe path may be available to permit the needle to circumvent vital body organs lying along the desired puncture path. In such cases, the risk to the patient in reaching the target point may be so great as to prevent the use of, e.g. needle biopsy, and further medical diagnosis and treatment might then require exploratory surgery. This of course entails significant trauma, expense, time and manpower in conducting the surgery, and also entails added post-operative time and expense.
Heretofore, no device or method has ben found which alleviates the need for subjecting the patient to such trial and error needle positioning. Prior art trial and error methods of acomplishing percutaneous tumor biopsy and absecess drainage, and the risks associated therewith, are discussed in "Interventional Radiology of the Abdomen", Joseph T. Ferruci, et al., pp. 124-135 (Williams and Wilkins 1981); "Interventional Radiology", Athanasoulis, et al., PP. 561-583 (W. B. Saunders Co. 1982); and M. P. Heilbrun, et al., "Preliminary experience with Brown-Roberts-Wells (BRW) computerized tomography stereotaxic guidance system", J. Neurosurg. vol. 59, pp. 217-222 (1983), the disclosures of which are hereby incorporated by reference.
Devices which have been developed for cranial surgery and treatment include those disclosed in U.S. Pat. Nos. 3,115,140; 3,135,263; 4,294,119; and 4,350,159, and in Russian Patents 441,933 and 764,670. However, these devices are complex and cumbersome, and are not readily adaptable for use on body parts other than the head.